Photo Disclaimer
Description
San Francisco Garter Snake
Scientific Name: Thamnophis sirtalis tetrataenia
Common Name: San Francisco Garter Snake
Species Overview
Size: Adults typically reach 2.5–3.5 feet (0.75–1.1 m) in length, with a slender, streamlined body and keeled scales that give a slightly textured surface.
Appearance: The San Francisco Garter Snake is widely regarded as one of the most visually stunning snakes in the world. Its brilliant turquoise-blue lateral scales contrast with bold black stripes and a vivid red-orange dorsal stripe running the full length of the body. The head is bright red with black borders, and the belly is pale blue-green to white with subtle checkering. This dramatic combination of colours creates an iridescent effect, especially under natural sunlight. Each individual displays slight variations in tone and intensity, with some leaning more toward rich crimson or deep aquamarine.
Distribution: Endemic to the San Francisco Peninsula in California, USA, where it inhabits a very limited range.
Habitat: San Francisco Garter Snakes are found near ponds, marshes, and slow-moving streams surrounded by dense vegetation. In captivity, they thrive in naturalistic terrariums with soft substrate, climbing décor, and secure hiding areas, along with a large water dish for soaking.
Behaviour: These snakes are diurnal and highly active, often basking during the day and retreating into vegetation or burrows at night. They are alert and fast-moving but calm once accustomed to handling. Their intelligence and curiosity make them both engaging and rewarding to observe.
Captive Care
Enclosure: Provide an enclosure at least 3–4 feet in length for adults. Include multiple hides, smooth rocks, and sturdy branches for climbing and basking. Use soft, moisture-retaining substrate such as soil, coconut fibre, or cypress mulch. A large, clean water dish should always be available for soaking.
Temperature & Humidity: Maintain a daytime gradient of 75–85°F (24–29°C) with a basking area near 88°F (31°C). Allow nighttime drops to 68–72°F (20–22°C). Maintain humidity between 60–75%, ensuring good airflow and access to clean, fresh water daily.
Diet: Offer a varied diet of thawed rodents, earthworms, fish (avoid high-thiaminase species), and frogs. Although they can adapt to rodent-based feeding, these snakes thrive best on a natural, diverse diet. Due to their fast metabolism, juveniles should be fed every 2–3 days and adults every 3–5 days.
Behaviour in Captivity: San Francisco Garter Snakes are intelligent, observant, and lively. They are visually engaging and respond well to regular care routines. With patience, they become confident and interactive, often remaining visible and active during daylight hours.
Special Considerations: This species may be housed singly or in small groups, but careful supervision is essential during feeding to prevent competition or accidental bites. As a protected species in the wild, captive-bred individuals should always be sourced from reputable, legal breeders.
Genetics Note
The San Francisco Garter Snake is not known for captive morphs due to its rarity and conservation status. Natural variation occurs in stripe brightness and hue, with some individuals exhibiting more intense turquoise or red coloration. Selective breeding within legal captive populations has focused on maintaining vibrancy rather than altering genetic traits.
Species Summary
The San Francisco Garter Snake (Thamnophis sirtalis tetrataenia) is one of the most prized and well-recognized garter snakes in herpetoculture. Its unmatched beauty, intelligent behaviour, and ecological importance make it both a visual centerpiece and a symbol of successful conservation efforts. With proper care, this active and striking species thrives in captivity, rewarding keepers with vibrant colouration and engaging daily activity.